Highwall mining is applied in harvesting coal, minerals, ores or other materials in seams or veins under an overburden, which may be accessed from an exposed edge of the seam or vein. Highwall mining is applicable where a continuous mining machine can be placed in a cut or trench to extend a cutter module, followed by a train of conveyor segments (or units) as the cutter module advances, into a substantially horizontal shaft under the overburden. Usually a train of segments for Highwall mining comprises a cutter module, a train of conveyor segments, provided with a conveyor for transporting mined material from and to opposite adjacent conveyor segments in the train of conveyor segments and a drive for the cutter module and conveyors. U.S. Pat. No. 7,717,522 describes a conveyor segment for use in a train of conveyor segments for Highwall mining.
The cutter drum is one of the most important wear items on a continuous mining machine. The cutter drum constitutes an important limit on the machine's excavation (sump) speed and efficiency. Improvements to cutter drum designs that make them last longer, allow them to apply greater forces to the seam drive (tunnel) face, and/or can improve the economics of excavating seam drives with a continuous mining machine.
In some circumstances, environmental conditions in the mining area near or at the cutter module can hamper efficient mining. For example, a very low (thin seam) mining shaft with ample shear-up and limited cutter-drum cutting space can decrease the mining capacity due to limited roller bearing capacities and cutting vibrations at the expense of mined material. In addition, such circumstances may also cause damage to parts of the mining equipment like cutter drives, x-pair tapered roller bearings, seals, gear boxes, and shear arms. U.S. Pat. No. 7,997,659 describes a rotary cutter for tunnel boring machine which can be used in low mining shaft applications.